1997 Marlin Hunter 2.3 inj ford runs rough at 3000 RPM under load

[dbazdavies]

Re: 1997 Marlin Hunter 2.3 inj ford runs rough at 3000 RPM under load

I had a 2.3 Scorpio manual--- started it one day and it started knocking like loose tappets - it was the timing chain - as all the plastic guides that route the chain around the front of the engine had fallen to bits - seems its a common problem !!

[danny_nelson]

Re: 1997 Marlin Hunter 2.3 inj ford runs rough at 3000 RPM under load

It is clear from your back ground that you are more than capable of sorting this out. I have known other Marlins fitted with the 8 valve twin cam and the 16 valve, and with the Zetec suffer with what you are describing. I had good results with one by re routing the (trunk) and air filter.
Danny.

[peterboat]

Re: 1997 Marlin Hunter 2.3 inj ford runs rough at 3000 RPM under load

It is clear from your back ground that you are more than capable of sorting this out. I have known other Marlins fitted with the 8 valve twin cam and the 16 valve, and with the Zetec suffer with what you are describing. I had good results with one by re routing the (trunk) and air filter.
Danny.

Yes Danny I had decided that the filter couldnt be in a worse place even if they tried!! But as always its good to ask questions before embarking on major work for what could be a simple fix. I will look at the things that people have highlighted, as they are all possibles especially the EGR which I have know cause havoc on Jag diesels in some cases wrecking the engines!!

[peterboat]

Re: 1997 Marlin Hunter 2.3 inj ford runs rough at 3000 RPM under load

Well yesterday I cleaned the MAF, and then rigged up a shield to stop the air filter picking up hot air from the radiator, slight improvement when I went out for a run. Also when the engine is cold the problem is not present
So last night we went to a friends 20 miles away engine running fairly hot problem still there. On way home at 2300 hrs no problem whatsoever, so a combination of the shield and the cool of the evening sorted the problem out.
So now its down to having a crossflow radiator made for the beast and moving the air filter to a lower position with an extended trunking to help smooth the air flow pre MAF

[peterboat]

Re: 1997 Marlin Hunter 2.3 inj ford runs rough at 3000 RPM under load

So today has been much cooler and the problem has nearly gone away so its definitely heat related so I will move the pick up from where it is to pick up cold air. At the same time I will have a new rad made in crossflow pattern to increase the marginal cooling of the original radiator.
So it would appear that all along the problem has been due to very hot weather of last week which coincided with the fuel pump seizing up!! still it keeps us occupied doesnt it?

[dcunn]

Re: 1997 Marlin Hunter 2.3 inj ford runs rough at 3000 RPM under load

Glad you seem to be sorted, however if it persists here's another thought :
Could it be that the temperature sensor unit could be giving false readings to the ecu if the car only has problems when it's hot.
There may be two sensors on this engine, one sending to the temperature gauge and one sending to the ECU.
Temperature is crucial to fuel mixture.

Rgds DC

[chris_cussen]

Re: 1997 Marlin Hunter 2.3 inj ford runs rough at 3000 RPM under load

There are indeed to water temperature sensors, one to the ECU and one to the gauge. In addition there is an air temperature sensor in the manifold.

[peterboat]

Re: 1997 Marlin Hunter 2.3 inj ford runs rough at 3000 RPM under load

Could be have had these problems in a Jag in the past. I will move the air filter into cold air and replace the radiator first as they are an issue especially the radiator its on the limit to say the least

[PeterM]

Re: 1997 Marlin Hunter 2.3 inj ford runs rough at 3000 RPM under load

Hi Peterboat
I'm interested to hear your progress.
Has your hunter always had this misfire?
If it used to run normally but now does not then it is unlikely to be due to the position of the air intake unless you have changed this.
Similarly it is unlikely to be due to the radiator unless this is clogged and failing or you have altered it. You could test this by flushing it out then testing its temperature when running fully hot ( fan on, meaning thermostat fully open) using an infrared thermometer (£10 on eBay) to look for cold areas where coolant is not circulating. Cheaper than a new radiator!
A sensor problem still seems the more likely explanation.
Best wishes
Peter

[peterboat]

Re: 1997 Marlin Hunter 2.3 inj ford runs rough at 3000 RPM under load

It is heat related now the air temp is reduced the problem has all but gone away the air filter shouldnt be where it is as this is bad engineering practice hot air reduces power and can cause other issues. The radiator is at the end of its life as soon as you drive hard its cooling becomes marginal. I will fit a new crossflow dad and move the airfilter as well and I am sure all the hot day running issues will be cured

[davidmartin720]

Re: 1997 Marlin Hunter 2.3 inj ford runs rough at 3000 RPM under load

I have been following this thread with interest as the Hunter I recently bought has a similar problem, sometimes when cold it will not pick up, or it can refuse when hot to accelerate without playing with the throttle. I do not feel it has the power it should have for a 2.1 litre DOHC EFI. A lot of the time it goes well when pushed, this is on a hot day with the air cleaner behind the radiator in the original place. What is the expected top end revs on the clock? I made an enquiry yesterday at a local ECU garage about checking for faults. He took the ECU details and checked that he can download all the relevant data, so later next week or the week after, "Watch this space", hopefully you will see the back end of the Hunter disappearing into the distance. David.

[davidmartin720]

Re: 1997 Marlin Hunter 2.3 inj ford runs rough at 3000 RPM under load

An update to my last post. I have been under the hospital for the past 16 months so I have only travelled about 1,000 miles in my Hunter. In May a car Electrical firm that deals with ECUs and remapping looked at my car and said they could find nothing wrong. To my mind it still ran exactly the same, no power. I changed the HP fuel pump, no difference, when pushed it went into "limp mode". Last week I took the car to another Car electrical firm [the same firm "DroverPete" went to, and they did various checks: Codes stored in ECU indicated faults with road speed sensor and carbon canister valve which are not fitted. A fault with the lambda sensor was also stored but found to be working correctly. Fuel injection system checked and ok. Road tested and found the car ran really well.
Driving the car this weekend it was "Magic", how I thought it should have run from the beginning, the garage did not try it before working on it so they do not know what fault they have corrected. Watch the rear of the Hunter disappearing in the distance. David.

[David]

Re: 1997 Marlin Hunter 2.3 inj ford runs rough at 3000 RPM under load

Well done, I like it when people post good news stories...

[seasider790]

Re: 1997 Marlin Hunter 2.3 inj ford runs rough at 3000 RPM under load

Great to hear that you finally have your Hunter running as you always thought it should have, David. It's also good to hear that you're well enough to get out and enjoy the car. Sunday really was a glorious day for being out in an open top car, wasn't it? I did a lovely tour along the coast as far as Porlock and it felt more like August than October at times!

Paul